Muffled roasting-furnace.



H. M. RIDGE.

MUPFLBD ROASTING FURNACE.

APPLICATION FILED MARA 9, 1911.

Patented Allg. 19, 1913. I 2 sums-SHEET 1.

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H. M. RIDGE.

MUFFLBD ROASTING FURNACE.

APPLIUATION FILED MAR. 9, 1911.

l O70 534. Patented Aug. 19, 1913. 9 2 SHEETS-SHEET 2.

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coLuMum PL/NouuAm-l, co.. WASHINGTON. n. c.

UNITED STATES PATENT OFFICE.

HARRY' MAGKENZIE RIDGE, oF LON-DON, ENGLAND.

IVIUFELED ROASTING-FURNACE.

To all whom t may concern Be it known that I, HARRY MAGKENZIE RIDGE, a subject of the King of Great Britain, residing at 62 London Wall, in the city of London, England, mining engineer, have invented certain new and useful Improvements in Muifled Roasting- Furnaces, of which the followingv is a specication.

This invention is a roasting furnace having mechanically operated stirrers mounted upon two' or more vertical shafts in which the flues for the roasting gases are constructed so that there is no communication between them and the roasting hearth or hearths. rabbling of the ore is regular and does not involve opening the working doors of the furnace, the disadvantages attendant upon stirring the ore by hand in known muffled roasting furnaces are entirely obviated.

In the accompanying drawings Figure l is an elevation of one arrangement of roasting furnace constructed in accordance with my invention; Fig. 2 is a longitudinal section on line A-B of Fig. 3, which is a horizontal section on line C-D of Fig. 2; Fig. 4c is a transverse section of the furnace in the plane of one of the rabble shafts; Figs. 5, 6 and 7 are longitudinal sections showing modified arrangements of lines.

The furnace therein sho-wn has three superimposed mufiies a, Z), c which are heated by the heating fine d, which first passes beneath the hearth of the bottom muffle c,

thence upward and along in the reverse direction between the muflles b and c. On the longitudinal center line of the muifles is a series of vertical shafts c each of which, except the one at the right hand end, passes through all three muflles and is supported beneath the furnace in a footstep bearing. The shafts are revolved in the usual manner by means of worm gearing f running in oil and inclosed in dust-proof covers, and gastight oints are made at the top of the furnace by means of water seals g at the points where the vertical shafts pass through the arch or crown of the furnace. Where these shafts pass through the heating flue they are insulated by means of rebrick or other refractory non-conducting material which serves the double purpose of preventing transference of heat to the shafts and leakage of the furnace gases into the muffles. The shafts are fitted with rabble arms z' and are arranged at varying distances apart so Specification of Letters Patent.

Application led March 9, 1911.

Since the mechanical stirring orr Patented Aug.-19,19'13.

serial No. 613,225.

that the path of the stirrers ory rabbles in some cases cuts into the Zone of the adjacent rabble only very slightly, while in other cases the two zones overlap to a very considerable extent, so as to insure a thorougl'r mixing of the ore. llVhere the rabble path only cuts but slightly into the adjoining Zone, the rabbles are so designed that the passage of the ore from the one Zone to the other can take place only in one direction. By this means the material while' being roasted, passes gradually along the furnace until it reaches the last raibbling Zone of a given hearth, in= the case of furnaces with multiple superimposed hearths, where it is stirred in gradually decreasing circles until it reaches an opening near the shaft, in that Zone, throughv which opening the material drops to the inclosed mule below it. The openings may be in any convenient position. rFwo of such openings are indicated in Fig. Q, one being shown in full lines at Z and the other' in broken lines at m.

The raw material is introduced into the top muftle through a suitable opening such as and passes successively through the various rabbling Zones in the top muffle or hearth a until it reaches the last Zone from which it passes through the drop hole Z on to the hearth of the next mufle Z2 which it traverses in the opposite direction until it reaches the drop hole m through which it passes to the lowest muflle c, traversing it and eventually passing out of the furnace through the discharge opening a. The roasting gases travel in the opposite direction to the ore from the furnace 7L under the bottom muffle c, thence by the vertical passages y' to the gas flue cl between the top of the muffle c and the hearth of the muffle b and along this flue in the direction opposite to the travel of the ore in the muffle thence 4either to the atmosphere as shown in Fig. 2

at d or alternatively as in Fig. 5 by vertical flues j to a gas flue Z2 between the top of the muffie and the hearth of the mufle a and along this flue to a gas outlet (Z3. Alternatively, the gas flue instead of passing between the top of the second muflie and the hearth of the uppermost mulfle, as in Fig. 5, may be taken as in Fig. 6 by vertical passages j2 to a flue Z4 above the top of the top muffle a to an outlet d5. Again the gas flue in addition to passing between the middle and uppermost muflles may be taken, as in Fig. 7 above the latter muffle by means of vertical passages and flue d6 to an outlet (Z7.

As that part of the hearth of the lowest muftle which is near to or extends over the furnace grate is subject to very rapid wear owing to high and unequal temperatures, it is preferred that this end of the lowest muffle together with the furnace should extend beyond the end wall of the upper mulile so as to enable this part to be cut off from the remainder by blocking the flue Z near the furnace end and to be renewed or repaired witho-ut serious interruption to the operation of the furnace.

The number of superimposed muifles may vary according to circumstances and the nature of the material to be roasted and similarly the number of vertical shafts and the arrangement of the rabbling zones may likewise be varied to suit particular requirements.

Having thus described the nature vof this invention and the best means I know of carrying the same into practical effect, I claim z- 1. A muffled roasting furnace, comprising` in combination a furnace, a muflle having a material feed inlet and discharge out-let, a plurality of mechanically rotated vertical shafts passing through the inutile, a radial rabble arm fitted to each shaft, the said shafts being arranged at varying distances Aapart so that the paths of the ends of adjacent rabble arms in some cases overlap slightly and in other cases overlap to a considerable extent, means for gradually passing the material fed into the muffle toward the discharge outlet, and a flue communieating with the furnace and passing below the hearth of the muflie whereby the latter may be heated without admixture of the heating gases from the furnace with the gases from the material being treated.

2. A muffled roasting apparatus, comprising in combination, a furnace, a series of superimposed and intercommunicating muffles, an inlet in the uppermost muflie for the introduction of materials to be treated, a discharge outlet in the lowermost hearth, a

plurality of mechanically rotated vertical shafts passing through the muflies, radial rabble arms carried by the shafts, the said shafts being arranged at varying distances apart so that the paths of the ends of adjacent rabble arms in each muflie in some cases overlap slightly and in other cases overlap considerably, means for passing the material fed into the apparatus successively along the muflies toward the said discharge outlet, and flues communicating with the furnace and passing in proximity of the muflles whereby the latter may be heated without admixture of the heating gases from the furnace with the gases from the material under treatment.

3. A muffled roasting apparatus, comprising in combination, a furnace, an upper inutile, a lower muflle having an end superimposed above the furnace and extending beyond the end of the upper muliie, the upper mnlfle having an inlet for the introduction of material to be treated and an outlet communicating with the lower mullie, a discharge outlet in the lower muflie, a rotatable vertical shaft passing through the projecting end of the lower muflie, a plurality of similar shafts passing through the muflies, radial rabble arms carried by the shafts, the said shafts being arranged at varying distances apart so that the paths of the ends of adjacentrabble arms in each muflle in some cases overlap slightly and in other cases overlap considerably, means for passing the material fed into the apparatus successively along the inutiles toward the said discharge outlet, and flues communicating with the furnace and passing in proximity of the muilles whereby the latter may be heated without admixture of the heating gases from the furnace with the gases from the material under treatment.

In testimony whereof I have signed my name to this specication in the presence of two subscribing witnesses.

HARRY MACKENZIE RIDGE.

Vitnesses Josnrn UILLARD, W. J. MoRwooD.

Copies of this patent may be obtained for ive cents each, by addressing the Commissioner of Patents,

' Washington, ID. C. 

